Satiety associated with calorie restriction and time-restricted feeding: Central neuroendocrine integration

Authors: TACAD, DEBRA - University Of California, Davis; TOVAR, ASHLEY - University Of California, Davis; RICHARDSON, CHRISTINE - University Of California, Davis; Horn, William; Keim, Nancy; KRISHNAN, GIRI - University Of California, San Diego; KRISHNAN, SRIDEVI - University Of California, San Diego

Submitted to: Advances in Nutrition
Publication Type: Review Article
Publication Acceptance Date: 2/2/2022
Publication Date: 2/4/2022
Citation: Tacad, D.K., Tovar, A.P., Richardson, C.E., Horn, W.F., Keim, N.L., Krishnan, G.P., Krishnan, S. 2022. Satiety associated with calorie restriction and time-restricted feeding: Central neuroendocrine integration. Advances in Nutrition. 13(3):758-791. https://doi.org/10.1093/advances/nmac011.
DOI: https://doi.org/10.1093/advances/nmac011

Interpretive Summary: The prevalence of obesity is high in the US population, and more research is needed to understand why attempts for sustaining weight loss are often unsuccessful. In this review paper, we have summarized current knowledge of how the brain and nervous system receive and coordinate signals related to provoking hunger or experiencing satiety. To understand how two approaches to dieting, continuous caloric restriction and time-restricted feeding, we have reviewed how the body's natural rhythms affected by light and eating play a role in eating behavior. The evidence suggests that with a continuous caloric restriction, hunger is elevated and satiety is suppressed. Reduced hunger and less suppression of satiety may occur with time-restricted feeding compared to that observed in with continuous caloric restriction. If the time-restricted feeding approach is used achieve a caloric restriction, these observations may be instrumental in the improving adherence to such a diet in the longer run. However, more research on time-restricted feeding is needed to confirm this possibility.

Technical Abstract: This review focuses on summarizing our current knowledge on how TRF and CR affect central neuro-endocrine systems involved in regulating satiety. This is part 2 of a two-part review series, where part 1 summarizes the effect of CR and TRF on peripheral endocrine mechanisms in the regulation of satiety. Several interconnected regions of the hypothalamus, brainstem, and cortical areas of the brain are involved in the regulation of satiety. Calorie restriction (CR) can influence the primary circadian clock, which is a light entrainable oscillator located in the suprachiasmatic nucleus in the hypothalamus. Time-restricted feeding (TRF) may affect this and the peripheral clocks (clock genes, metabolic clocks and potentially the elusive food entrainable oscillator). The peripheral clocks are influenced by the primary circadian clock, but also entrained by food timing, sleep timing and other lifestyle parameters, which can supersede the metabolic processes that are regulated by the primary circadian clock. Further, there is also limited evidence suggesting that the hunger systems (based on mRNA expressions of neuropeptide Y) in the hypothalamus are elevated, while satiety (based on mRNA expression of pre-opiomelanocortin neurons) is suppressed following CR. Both hunger and satiety mechanisms are affected by TRF, suggesting that reduced hunger and less suppression of satiety is likely in TRF compared to that observed in CR. These observations may be instrumental in the ability to adhere to CR in the longer run, if implemented using the TRF approach. However, these suggestions are based on only a few of studies, and future studies that use standardized protocols for the evaluation of the effect of these diet patterns (time, duration, meal composition, sufficiently powered) are necessary to verify these preliminary observations.